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R.J.M. Klein Gebbink

Bio: R.J.M. Klein Gebbink is an academic researcher from Utrecht University. The author has contributed to research in topics: Palladium & Pincer movement. The author has an hindex of 14, co-authored 38 publications receiving 706 citations. Previous affiliations of R.J.M. Klein Gebbink include Radboud University Nijmegen & Johns Hopkins University.

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TL;DR: In this article, the authors showed that the deactivation of polylithiated, carbosilane (CS) dendrimers is caused by irreversible formation of catalytically inactive Ni(III) sites on the periphery of these dendrilers.
Abstract: Transmetalation of polylithiated, carbosilane (CS) dendrimers functionalized with the potentially terdentate ligand [C6H2(CH2NMe2)2-2,6-R-4]- ( = NCN) with NiCl2(PEt3)2 produced a series of nickel-containing dendrimers [G0]-Ni4 (4), [G1]-Ni12 (5), and [G2]-Ni36 (7) in moderate to good yields. The metallodendrimers 4, 5, and 7 are catalytically active in the atom-transfer radical addition (ATRA) reaction (Kharasch addition reaction), viz. the 1:1 addition of CCl4 to methyl methacrylate (MMA). The catalytic data were compared to those obtained for the respective mononuclear compound [NiCl(C6H2{CH2NMe2}2-2,6-SiMe3-4)] (2). This comparison indicates a fast deactivation for the dendrimer catalysts beyond generation [G0]. The deactivation of [G1]-Ni12 (5) and [G2]-Ni36 (7) is caused by irreversible formation of catalytically inactive Ni(III) sites on the periphery of these dendrimers. This hypothesis is supported by results of model studies as well as ESR spectroscopic investigations. Interestingly, the use of two alternative nickelated [G1] dendrimers [G1]*-Ni12 (11) and [G1]-Ni8 (15), respectively, in which the distance between the Ni sites is increased, leads to significantly improved catalytic efficiencies which approximate those of the parent derivative 2 and [G0]-Ni4 (4). Preliminary membrane catalysis experiments with [G0]-Ni4 (4) and [G1]-Ni12 (5) show that 5 can be efficiently retained in a membrane reactor system. The X-ray crystal structure of the Ni(III) complex [NiCl2(C6H2{CH2NMe2}2-2,6-SiMe3-4)] (16), obtained from the reaction of 2 with CCl4, is also reported.

186 citations

Journal ArticleDOI
TL;DR: A series of cyclopalladated carbosilane dendrimers functionalized with monoanionic [C6H4(CH2NMe2)-4]- (= CN) C,N-chelating ligands via a multiple and selective C-H bond activation process have been prepared in this paper.

58 citations

Journal ArticleDOI
TL;DR: New chiral NCN-pincer palladium complexes containing bulky diphenylhydroxymethyl pyrrolidinyl moieties as chiral auxiliaries have been synthesized.

54 citations

Journal ArticleDOI
TL;DR: In this paper, a series of meso-tetrakis(SCS-pincer PdCl)−(metallo)porphyrin hybrids have been synthesized using two distinct synthetic routes.

46 citations

Journal ArticleDOI
TL;DR: In this paper, a P-stereogenic bis-phosphoramidite pincer palladium complexes were derived from (S)-(−)-α,α-diphenyl-2-pyrrolidinemethanol and (S)(+)-indolinemethyl-indolinerethanol.

41 citations


Cited by
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10 Mar 1970

8,159 citations

Journal ArticleDOI
TL;DR: This review discusses the synthetic methodologies that are currently available for the preparation of platinum group metal complexes containing pincer ligands and especially emphasizes different applications that have been realized in materials science such as the development and engineering of sensors, switches, and catalysts.
Abstract: Since the first reports in the late 1970s on transition metal complexes contain- ing pincer-type ligands—named after the particular coordination mode of these ligands—these systems have at- tracted increasing interest owing to the unusual properties of the metal centers imparted by the pincer ligand. Typical- ly, such a ligand comprises an anionic aryl ring which is ortho,ortho-disubsti- tuted with heteroatom substituents, for example, CH2NR2 ,C H 2PR2 or CH2SR, which generally coordinate to the met- al center, and therefore support the MC s bond. This commonly results in a terdentate and meridional coordina- tion mode consisting of two metalla- cycles which share the MC bond. Detailed studies of the formation and the properties of a large variety of pincers containing platinum group metal complexes have provided direct access to both a fundamental under- standing of a variety of reactions in organometallic chemistry and to a range of new applications of these complexes. The discovery of alkane dehydrogenation catalysts, the mecha- nistic elucidation of fundamental transformations (for example, CC bond activation), the construction of the first metallodendrimers for sustain- able homogeneous catalysis, and the engineering of crystalline switches for materials processing represent only a few of the many highlights which have emanated from these numerous inves- tigations. This review discusses the synthetic methodologies that are cur- rently available for the preparation of platinum group metal complexes con- taining pincer ligands and especially emphasizes different applications that have been realized in materials science such as the development and engineer- ing of sensors, switches, and catalysts.

1,413 citations

Journal ArticleDOI

1,307 citations

Journal ArticleDOI
TL;DR: 2. Thiol Oxidation to Disulfides 3007 3. Epoxidation of Alkenes 3007 4.Oxidation of Bromide 3008 5. Oxidation of Mercaptoethanol by Dioxygen 3008 V.
Abstract: 2. Thiol Oxidation to Disulfides 3007 3. Epoxidation of Alkenes 3007 4. Oxidation of Bromide 3008 5. Oxidation of Mercaptoethanol by Dioxygen 3008 V. Particle−Dendrimer Assemblies 3008 1. Hydrogenation 3008 2. Heck Reaction 3010 3. Anodic Oxidation of Ethanol 3010 VI. Redox Catalysis 3010 1. Anodic Oxygen Reduction 3010 2. Cathodic Reduction of CO2 to CO 3010 3. Ferrocenes as Redox Mediators for Glucose Oxidation 3010

961 citations